Tailor-made cleavage site attenuates influenza B

Evaluation of: Stech J, Garn H, Herwig A etal. Influenza B virus with modified hemagglutinin cleavage site as a novel attenuated live vaccine. J. Infect. Dis. 204(10), 1483-1490 (2011).
Influenza B viruses contribute significantly to human influenza. The circulation of two antigenically divergent lineages of this virus can reduce the efficacy of licensed influenza vaccines. A novel live-attenuated influenza B vaccine candidate has been generated by creating a virus that strictly requires elastase activity for the accurate proteolytic maturation of its hemagglutinin. This mutant influenza B virus grows to high titers in vitro and is strongly attenuated in mice, yet it induces a robust protective immune response in this host. The findings on this tamed influenza B virus and its potential prospects are discussed.